Fearless Refactoring and

the Art of Argument-Free Rust

Ed Jones, RustConf ’24

• I work at Canonical
• I like clean code
• I annoy my coworkers

industry’s hard problems

industry’s hard problems

• requirements
• politics
• maintenance

what is maintainable?

what is maintainable?

• simple
• easily-understood
• predictable

for whom does the coder code?

for whom does the coder code?

• customers and consumers
• coworkers
• themselves

Fearless Refactoring

Fearless Refactoring

after making a change, the next time all tooling passes,
code likely still works as intended

good practices

good practices

• match exhaustively
• mutate in well-defined regions
• limit unsafety

good code

good code

• predictable
• clear flow of concepts
• obvious responsilbilities
• sparingly weird

weird code

weird code

• draws the eye
• result of uncoordinated practices
• resolved by debate

The Art of Argument-free Rust

The Art of Argument-free Rust

note: not debate-free

how we’ve avoided arguments

how we’ve avoided arguments

• office hours (‘Rust Surgery’)
• cross-team code-review
• standardisation docs

standardisation docs

standardisation docs

• provide a reference point for best-practices
• provide rationale for particular decisions
• show benefits with clear examples

the process

the process

1. note repeated arguments
2. write up generally-applicable notes
3. review with a few experienced Rustaceans
4. review with many Rustaceans
5. release

the process (hard-mode)

1. note repeated arguments
2. write up generally-applicable notes
3. review with a few experienced Rustaceans
4. review with many Rustaceans
5. release

the process (easy-mode)

the process (easy-mode)

github.com/canonical/rust-best-practices

what’s next?

what’s next?

• more standards
• automation

thanks for listening!